help with herbs

Hey all!
I am new to this community. I joined because I love gardening, and I can always use advice for bettering my plant care.
Currently I am an apartment dweller. The apt. has a good number of large windows which recieve both mornign and afternoon sun.
My herb situation=
I have two 2' window boxes. The first box is seprated into three sections. Section 1 houses sweet basil, secion 2 contains italian parsley and oregano inhabits the 3rd section.
The second box houses mint, lemon balm and lavender.
My problem=
Recently, the herbs (except for the parsley) have wilted. many of the leaves have been turning half brown. I've been keeping the soil damp (like a wrung out sponge) and i let the soil dry out for a couple of days between waterings...
Any clues as to what's going on? Should I give the herbs direct sun? Less sun? More/Less water? Replant them into bigger or seperate containers?
Any help is very much appreciated.
Thank you!